1. Field of the Invention
The present invention relates to a novel and improved slam-capable, flush-mountable, T-handle operated rotary latch assembly connected to rear portions of a pan-shaped housing, with a pair of pivotal operating arms that rotate together with the T-handle in a forward direction of rotation to operate or xe2x80x9cunlatchxe2x80x9d the latch, wherein the operating arms engage stops defined adjacent a backwall of the housing to limit reverse direction rotation of the operating arms and the T-handle, and wherein a key operated lock may be provided to retain the operating arms in their non-operated positions. More particularly, the present invention relates to a T-handle operated rotary latch unit of the type described that preferably employs a rotary latch assembly of the type having a single rotary jaw that is releasably retained in its latched position by a rotary pawl, with the latch having spaced first and second housing side plates that sandwich the rotary jaw, the rotary pawl and a torsion spring that biases the jaw toward an open position, with the side plates defining aligned first and second U-shaped notches that cooperate with a third U-shaped notch formed in the rotary jaw to concurrently receive and to latchingly retain a suitably configured strike formation, and with one of the housing side plates being rigidly connected to the pan-shaped housing by at least a tab-like formation that overlies the backwall and defines one of the stops, wherein pivotal movement of the operating arms trips a release trigger of the pawl in response to operation of the T-handle to permit the rotary jaw to be pivoted by the torsion spring to an open position.
2. Prior Art
Flush mountable, paddle handle operated latches and locks are known that employ rotary latch bolts, also referred to as xe2x80x9crotary jaws,xe2x80x9d wherein the jaws are provided with U-shaped strike-receiving notches for latchingly receiving and releasably retaining suitably configured strike formations. It also is known to utilize a spring-biased operating arm that is pivotally connected to a back wall of a pan-shaped housing to transfer unlatching movement from a rearwardly extending projection of a housing-pivoted paddle handle to a rotary latch assembly that is connected to the pan-shaped housing, as is exemplified by U.S. Pat. No. 5,586,458 issued Dec. 24, 1996 to Lee S. Weinerman et al, entitled HANDLE OPERABLE ROTARY LATCH AND LOCK, and U.S. Pat. No. 4,320,642 issued Mar. 23, 1982 to John V. Pastva, Jr., entitled PADDLE LOCKS WITH HANDLE DISCONNECT FEATURES, the disclosures of which are incorporated herein by reference.
Other disclosures of latch and/or lock units that employ rotary jaws are found in U.S. Pat. No. 4,320,642 issued Mar. 23, 1982 to. John V. Pastva, Jr., entitled PADDLE LOCKS WITH HANDLE DISCONNECT FEATURES; U.S. Pat. No. 4,917,412 issued Apr. 17, 1990 to Jye P. Swan et al, entitled VEHICLE DOOR LOCK SYSTEM PROVIDING A PLURALITY OF SPACED ROTARY LATCHES; U.S. Pat. No. 4,896,906 issued Jan. 30, 1990 to Lee S. Weinerman et al entitled VEHICLE DOOR LOCK; and, U.S. Pat. No. 5,069,491 issued Dec. 3, 1991 to Lee S. Weinerman et al entitled VEHICLE DOOR LOCK SYSTEM. The disclosures of these patents also are incorporated herein by reference.
The rotary latch and/or lock units that are disclosed in the four patents identified just above are of a relatively heavy duty type that often are employed in xe2x80x9cpersonnel restraint applications,xe2x80x9d typically on doors of passenger compartments of vehicles. These heavy duty units employ pairs of lousing-mounted rotary jaws, with the jaws being sandwiched between pairs of housing side plates, and with notches that are formed in each pair of rotary jaws being configured to receive and engage opposite sides of a suitably configured strike formation, typically a cylindrical stem of a striker pin. While both of the housing side plates are provided with U-shaped notches, neither of these notches defines a strike engagement surface that cooperates with a notched rotary jaw to latchingly receive and releasably. retain a strike formation. The notches that are formed in the jaws, not the notches that are formed in the housing side plates, receive, engage and latchingly retain suitably configured strike formations.
Lighter duty rotary latch and lock units that employ single rotary jaws also are known, as exemplified by the following: U.S. Pat. No. 5,884,948 issued Mar. 23, 1999 to Lee S. Weinerman et al, entitled ROTARY LATCH AND LOCK; U.S. Pat. No. 5,611,224 issued Mar. 18, 1997 to Lee S. Weinerman et al, entitled HANDLE OPERABLE ROTARY LATCH AND LOCK; U.S. Pat. No. 5,586,458 issued Dec. 24, 1996 to Lee S. Weinerman et al, entitled HANDLE OPERABLE ROTARY LATCH AND LOCK; U.S. Pat. No. 5,564,295 issued Oct. 15, 1996 to Lee S. Weinerman et al, entitled HANDLE OPERABLE ROTARY LATCH AND LOCK; U.S. Pat. No. 5,439,260 issued Aug. 8, 1995 to Lee S. Weinerman et al, entitled HANDLE OPERABLE ROTARY LATCH AND LOCK; and, U.S. Pat. No. 4,312,203 issued Jan. 26, 1982 to Edwin W. Davis entitled FLUSH-MOUNTABLE LOCK WITH ACTUATOR DISCONNECT FEATURE.
While flush-mountable T-handle operated latch and lock mechanisms of various types are known, as is shown by U.S. Pat. No. 4,706,478 issued Nov. 17, 1987 to Jye P. Swan et al, entitled ROTARY HANDLE OPERATED DOOR LOCK, and while T-type operating handles are sometimes preferred over paddle-type operating handles in some applications, relatively little has been done until now to provide flush mountable, T-handle operated rotary latch assemblies that can be substituted for paddle handle operated rotary latch assemblies.
Although considerable thought has been devoted during recent years to providing improved, more compact and highly reliable handle-to-latch interconnection mechanisms in paddle handle operated rotary latches, it has seldom been possible to make much use of the resulting improvements in T-handle operated rotary latches. One of the reasons why improvements made in the handle-to-latch interconnection mechanisms of paddle handle operated rotary latches tend to be unsuitable for use in the handle-to-latch interconnection mechanisms of T-handle operated rotary latches has to do with the very different way in which paddle handles and T-handles connect to and pivot with respect to their associated pan-shaped flush mountable housings.
Whereas paddle handles execute a simple pivoting action about axes that parallel the back walls of their associated housings when moving between their non-operated and operated positions, T-handles ordinarily accomplish no unlatching movement at all when they pivot between their nested and extended positions about axes that substantially parallel the back walls of their associated housings; rather, they accomplish unlatching only when pivoted about axes that extend substantially perpendicular to the back walls of their associated housings. This very basic difference in the character and operation of the two types of handles has necessitated the use of very different handle-to-latch interconnection mechanisms on paddle-handle operated and T-handle operated rotary latch and lock units.
The present invention provides a slam-capable, flush-mountable, T-handle-operated, single-jaw rotary latch assembly having a jaw-retaining rotary pawl with an associated xe2x80x9ctriggerxe2x80x9d that can be tripped to xe2x80x9cunlatchxe2x80x9d the rotary latch by a compact arrangement of two independently movable operating arms that pivot in a forward direction alongside a back wall of the housing for executing an xe2x80x9cunlatchingxe2x80x9d movement in response to movement of the T-handle from its non-operated position to its operated position, with a compact arrangement of stops being provided adjacent the back wall for limiting the pivotal return movement of the operating arms and the T-handle as these three components return to their non-operated positions.
One feature of the invention resides in the provision of first and second independently movable operating arms that pivot alongside the back wall of a pan-shaped housing to drivingly connect a T-handle to a rotary latch assembly to operate, trip or unlatch the rotary latch assembly in response to pivotal movement of the T-handle from a non-operated position to an operated position. The first operating arm is relatively short and is rigidly connected to a stub shaft that is pivotally connected to the housing and carries the T-shaped grip of the operating handle. This first arm typically pivots through about a quarter-turn of movementxe2x80x94a range of usually about thirty degreesxe2x80x94when the T-handle is pivoted between the non-operated and operated positions. The second operating arm is relatively long, is pivotally connected to the back wall of the housing, and typically pivots through a much smaller range of movementxe2x80x94usually about fifteen degreesxe2x80x94to trip, operate or unlatch the rotary latch assembly by moving a trigger formation of the rotary latch assembly. The use of a pair of operating arms that cooperate in this manner, are of significantly different lengths and pivot through significantly different ranges of movement to provide the heart of a very compact and reliable handle-to-latch interconnection mechanism provides one feature of note.
Another feature resides in the manner in which stops are provided in a compact and reliable way to limit the return pivotal movement of not only the two operating arms but also the T-handlexe2x80x94movement that takes place as the result of the biasing action of a spring that is interposed between the housing and the second, relatively long operating arm. A return movement stop for the first, relatively short operating arm is provided by a formation of the first operating arm that is configured to engage a tab-like extension of one of the side plates of the rotary latch assemblyxe2x80x94an extension that overlies the back wall of the housing and is rigidly connected thereto to at least assist in mounting the rotary latch assembly on the pan-shaped housing. The use of a tab-like mounting formation of a rotary latch assembly to perform a second duty of providing a return movement stop for an operating arm that is connected to a T-handle (and therefore also serves to stop return pivotal movement of the T-handle) provides another feature of note.
Still another feature resides in the use of a formation of the first operating arm to stop the return pivotal movement of the second operating arm. Contemplated within the possibilities provided by this option are: 1) the use of engaged driving formations provided at distal ends of both of the operating arms to stop the return pivotal movement of the second operating arm; or 2) the provision of a stop surface at a xe2x80x9chubxe2x80x9d end of the first operating arm (adjacent the pivot axis of the first operating arm and adjacent a location of connection between the first operating arm and a stub shaft that carries the graspable T-shaped component of the T-handle) that is engaged by the second operating arm to stop the return pivotal movement of the second operating arm (an arrangement that can be utilized, if desired, to halt the return movement of the second operating arm before halting the return movement of the first operating arm); or, 3) the concurrent use of both of these types of stops (whereby spaced portions of the second operating arm engage spaced portions of the first operating arm to stop the return pivotal movement of the second operating arm at the same time that return pivotal movement of the first operating arm is stopped), in applications where dual-stop contact between the operating arms and concurrent stoppage of the movement of both operating arms may be desired.
Stating one feature of the invention in another way, while the stop that is defined by the tab-like extension of one of the side plates of the rotary latch assembly may effectively serve to limit the pivotal movement of both of the operating arms and the T-handle as these members pivot to their non-operated positions, a second stop defined by the first operating arm may be engaged by the second operating arm to independently halt the return pivotal movement of the second operating arm.
In preferred practice, the stop that is defined by the tab-like extension of one side plate of the rotary latch assembly serves to stop the return rotation of both of the operating arms. Where this preferred arrangement is employed, a single spring interposed between the housing and the second operating arm can be used to bias both of the operating arms into engagement with their respective stops to limit the return pivotal movement of the first and second operating arms and the T-handle when these three pivotal elements reach their non-operated positions.
While the preferred practice of the present invention calls for the use of rotary latch assemblies of the type disclosed in U.S. Pat. No. 5,586,458, it is contemplated that features of the invention including its advantageous arrangement of dual operating arms and their associated return-movement stops can be utilized with other types of rotary latch assemblies that are adapted by providing one of their housing side plates with a tab-like extension that overlies and is connected to a housing back wall at a location wherein the tab-like extension can serve dual duty as a mount for connecting the latch assembly to the back wall, and as a stop for limiting return pivotal movement of one of the operating arms that is connected to a T-handle, and therefore also serves to limit return pivotal movement of the T-handle.